Programmable assembly of pressure sensors using pattern-forming bacteria


Biological systems can generate microstructured materials that combine organic and inorganic components and possess diverse physical and chemical properties. However, these natural processes in materials fabrication are not readily programmable. Here, we use a synthetic-biology approach to assemble patterned materials. We demonstrate programmable fabrication of three-dimensional (3D) materials by printing engineered self-patterning bacteria on permeable membranes that serve as a structural scaffold. Application of gold nanoparticles to the colonies creates hybrid organic-inorganic dome structures. The dynamics of the dome structures’ response to pressure is determined by their geometry (colony size, dome height, and pattern), which is easily modified by varying the properties of the membrane (e.g., pore size and hydrophobicity). We generate resettable pressure sensors that process signals in response to varying pressure intensity and duration.



FDA Approves “Smart” Contact Lens Medical Device

SENSIMED Triggerfish® provides an automated recording of continuous ocular dimensional changes over 24 hours.

The patient wears the SENSIMED Triggerfish® system up to 24 hours and assumes normal activities including sleep periods.


SENSIMED Triggerfish® Sensor  Smart Contact Lens

The SENSIMED Triggerfish® Sensor is a soft disposable silicone contact lens embedding a micro-sensor that captures spontaneous circumferential changes at the corneoscleral area.

The adhesive SENSIMED Triggerfish® Antenna, which is placed around the eye, receives wirelessly the information from the contact lens.

The data is transmitted through a thin flexible cable from the Antenna to the portable recorder.

The portable recorder, worn by the patient, stores the acquired data during the monitoring session. At the end of the recording period, the data is transferred via Bluetooth from the recorder to the software previously installed on the practitioner’s computer.With its revolutionary technology, the SENSIMED Triggerfish® is a unique system providing further information on the continuous and natural changes of the eye over 24 hours.


Bacteria as Bio-Template for 3D Carbon Nanotube Architectures


It is one of the most important needs to develop renewable, scalable and multifunctional methods for the fabrication of 3D carbon architectures. Even though a lot of methods have been developed to create porous and mechanically stable 3D scaffolds, the fabrication and control over the synthesis of such architectures still remain a challenge. Here, we used Magnetospirillum magneticum (AMB-1) bacteria as a bio-template to fabricate light-weight 3D solid structure of carbon nanotubes (CNTs) with interconnected porosity. The resulting porous scaffold showed good mechanical stability and large surface area because of the excellent pore interconnection and high porosity. Steered molecular dynamics simulations were used to quantify the interactions between nanotubes and AMB-1 via the cell surface protein MSP-1 and flagellin. The 3D CNTs-AMB1 nanocomposite scaffold is further demonstrated as a potential substrate for electrodes in supercapacitor applications.


First Person: Herman O. Sintim

Herman O. Sintim, an organic chemist at Purdue University and a Sigma Xi Distinguished Lecturer, discusses novel ways to target bacteria that cause illnesses.

Antibiotic resistance is on the rise, and we are potentially facing a time when standard antibiotics simply won’t work anymore. Herman O. Sintim, an organic chemist at Purdue University and a Sigma Xi Distinguished Lecturer, is developing novel ways to target bacteria that cause illnesses. His approach is to prevent them from producing the toxins that lead to illness, rather than killing them. That kind of intervention avoids placing selection pressure on the bacteria, and so should reduce the chances that the bacteria will develop resistance to the intervention. Sintim discussed his research with managing editor Fenella Saunders.



3D Printing of Biomaterials Directly Onto Moving Body


At the 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) in Vancouver, Canada this week, researchers from the University of Minnesota are presenting a system that 3D prints objects directly onto a moving human body. It’s intended to put down layers of biomaterials that have been developed in the recent years, but which have been limited due to having to be made on a printer and then somehow transferred to the skin. As seen in the video below, the U of Minnesota system continuously tracks the hand while it’s under the printer, and adjusts the position of the nozzle to guarantee the correct position of every drop of bio-ink.


Topical tissue nano-transfection mediates non-viral stroma reprogramming and rescue


tnt_osu-wexner-medical-centerAlthough cellular therapies represent a promising strategy for a number of conditions, current approaches face major translational hurdles, including limited cell sources and the need for cumbersome pre-processing steps (for example, isolation, induced pluripotency)123456In vivocell reprogramming has the potential to enable more-effective cell-based therapies by using readily available cell sources (for example, fibroblasts) and circumventing the need for ex vivo pre-processing78. Existing reprogramming methodologies, however, are fraught with caveats, including a heavy reliance on viral transfection910. Moreover, capsid size constraints and/or the stochastic nature of status quo approaches (viral and non-viral) pose additional limitations, thus highlighting the need for safer and more deterministic in vivo reprogramming methods1112. Here, we report a novel yet simple-to-implement non-viral approach to topically reprogram tissues through a nanochannelled device validated with well-established and newly developed reprogramming models of induced neurons and endothelium, respectively. We demonstrate the simplicity and utility of this approach by rescuing necrotizing tissues and whole limbs using two murine models of injury-induced ischaemia.


Acoustically actuated ultra-compact NEMS magnetoelectric antennas


State-of-the-art compact antennas rely on electromagnetic wave resonance, which leads to antenna sizes that are comparable to the electromagnetic wavelength. As a result, antennas typically have a size greater than one-tenth of the wavelength, and further miniaturization of antennas has been an open challenge for decades. Here we report on acoustically actuated nanomechanical magnetoelectric (ME) antennas with a suspended ferromagnetic/piezoelectric thin-film heterostructure. These ME antennas receive and transmit electromagnetic waves through the ME effect at their acoustic resonance frequencies. The bulk acoustic waves in ME antennas stimulate magnetization oscillations of the ferromagnetic thin film, which results in the radiation of electromagnetic waves. Vice versa, these antennas sense the magnetic fields of electromagnetic waves, giving a piezoelectric voltage output. The ME antennas (with sizes as small as one-thousandth of a wavelength) demonstrates 1–2 orders of magnitude miniaturization over state-of-the-art compact antennas without performance degradation. These ME antennas have potential implications for portable wireless communication systems.


Micromotor-enabled active drug delivery for in vivo treatment of stomach infection

Advances in bioinspired design principles and nanomaterials have led to tremendous progress in autonomously moving synthetic nano/micromotors with diverse functionalities in different environments. However, a significant gap remains in moving nano/micromotors from test tubes to living organisms for treating diseases with high efficacy. Here we present the first, to our knowledge, in vivo therapeutic micromotors application for active drug delivery to treat gastric bacterial infection in a mouse model using clarithromycin as a model antibiotic and Helicobacter pylori infection as a model disease. The propulsion of drug-loaded magnesium micromotors in gastric media enables effective antibiotic delivery, leading to significant bacteria burden reduction in the mouse stomach compared with passive drug carriers, with no apparent toxicity. Moreover, while the drug-loaded micromotors reach similar therapeutic efficacy as the positive control of free drug plus proton pump inhibitor, the micromotors can function without proton pump inhibitors because of their built-in proton depletion function associated with their locomotion.41467_2017_309_fig1_html


Membrane-free culture and real-time barrier integrity assessment of perfused intestinal epithelium tubes



In vitro models that better reflect in vivo epithelial barrier (patho-)physiology are urgently required to predict adverse drug effects. Here we introduce extracellular matrix-supported intestinal tubules in perfused microfluidic devices, exhibiting tissue polarization and transporter expression. Forty leak-tight tubules are cultured in parallel on a single plate and their response to pharmacological stimuli is recorded over 125 h using automated imaging techniques. A study comprising 357 gut tubes is performed, of which 93% are leak tight before exposure. EC50-time curves could be extracted that provide insight into both concentration and exposure time response. Full compatibility with standard equipment and user-friendly operation make this Organ-on-a-Chip platform readily applicable in routine laboratories.


Beyond gut feelings: how the gut microbiota regulates blood pressure


Hypertension is the leading risk factor for heart disease and stroke, and is estimated to cause 9.4 million deaths globally every year. The pathogenesis of hypertension is complex, but lifestyle factors such as diet are important contributors to the disease. High dietary intake of fruit and vegetables is associated with reduced blood pressure and lower cardiovascular mortality. A critical relationship between dietary intake and the composition of the gut microbiota has been described in the literature, and a growing body of evidence supports the role of the gut microbiota in the regulation of blood pressure. In this Review, we describe the mechanisms by which the gut microbiota and its metabolites, including short-chain fatty acids, trimethylamine N-oxide, and lipopolysaccharides, act on downstream cellular targets to prevent or contribute to the pathogenesis of hypertension. These effects have a direct influence on tissues such as the kidney, the endothelium, and the heart. Finally, we consider the role of the gut microbiota in resistant hypertension, the possible intergenerational effect of the gut microbiota on blood pressure regulation, and the promising therapeutic potential of gut microbiota modification to improve health and prevent disease.